Under a condition that for example washings have a heavy stain part, a user sometimes performs hand washing of washings in advance and washes washings with a washing machine after the stain of washings is removed to a certain extent.
In addition, an inner part of a washing tank is divided into two regions including an upper region and a lower region by a partition plate; in the washing machine for separately washing washings in the upper and the lower regions, concaves and convexes in a wave pattern are formed on an upper surface or a lower surface of the partition plate, so that the partition plate can be appropriately removed from the washing tank to use as a washboard (referring to patent document 1).